Nursery rhymes are frequently hundreds of years old and their meanings are not clear but simply repeated or sung by young children. In the case of “Little Miss Muffet” she is eating a centuries old version of traditional curds and whey, which is your basic cottage cheese, probably the food that this rhyme depicts. Cottage cheese is drained, but the whey remains, leaving the individual curds loose. and the acidity removed to achieve a more sweet and pleasant taste.
Cheese curds are a necessary component in cheesemaking, which can also be fried for a snack or appetizer.These curds are solid pieces of curdled milk and made from fresh pasteurized milk in the process of creating cheese after bacterial culture and an acidic substance, like lemon juice, are added to cause clotting (curdling). For convenience, bakers frequently “curdle” milk to produce a buttermilk taste when making muffins, pancakes or other baked goods. Vinegar or lemon juice are the most common additive, but centuries ago rennet was used (cow's stomach lining). It is then cut into cubes and the result is a mixture of whey (the liquid) and curd. This mixture is cooked and pressed to separate the whey from the curd, creating the final product of cheese curd. Usually mild in flavor, fresh curds squeak when bitten into, a characteristic caused by air trapped inside the porous material. In the country of India, a popular alternative to meat is paneer, which is widely used in traditional main courses, and rice biryani. It resembles tofu and has a bland but pleasing taste and texture. (Okay, more than you wanted to know.)
Although cheese curds ideally should be eaten fresh, they can be purchased at local supermarkets nationwide, The most common curd is a young cheddar. In Wisconsin, cheese factories crank them out daily to satisfy the demand and have been produced since the mid 1800s, when cheesemaking got its start in America's Dairyland, as Swiss and German immigrants brought their skills and recipes to the Midwest. Today they are the state's most popular snack. Wisconsin produces over 2 billion pounds of cheese per year. That's a lot of curds.
A popular snack in the state of Wisconsin (no surprise), they have been enjoyed for years with wine or beer, but now have spread across the country, especially at county and state fairs, where they are usually deep-fried. They can be purchased at many local supermarkets.
So basically, Miss M was sitting on a stool eating cottage cheese until that spider showed up and ruined things for her. That should clear up any confusion you've had since childhood. These days she would likely be noshing on fried cheese curds and sipping a soft drink. Now go fry up some and enjoy.